The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Referring now to FIG. 1, an exemplary network system 10 includes a plurality of user equipment terminals (UE) 12-1, 12-2, . . . , and 12-N (collectively referred to as UE 12) that may include wireless terminals. Examples of wireless terminals include mobile phones, personal digital assistants (PDAs) and computers. The UE 12 may communicate with a home network 13 via a visited network 14. The home and visited networks 13, 14 may each include networks of service providers that may be in different countries, respectively. The home and visited networks 13, 14 may also each communicate with one or more packet data networks (PDNs) 15-1, 15-2. The PDNs 15-1, 15-2 communicate data as packets via Internet protocol (IP) addresses. An exemplary PDN is the Internet.
The home network 13 may include a home public land mobile network (HPLMN), and the visited network 14 may include a visited public land mobile network (VPLMN) of a 3rd Generation Partnership Project (3GPP™) network system. An exemplary home network 13 communicates with one or more visited networks.
Referring now to FIG. 2, the network system 10 is illustrated in more detail. The home network 13 includes a home PDN gateway 16 and an authentication/authorization/accounting (AAA) server 18. The PDN gateway 16 may communicate with a first PDN 15-1, such as the Internet. An exemplary UE 12 connects to the home network 13 via the visited network 14 through an attachment point. Once attachment to the home and visited networks 13, 14 is successful, the UE 12 may then connect to the first PDN 15-1. For example, the UE 12 may be a cellular phone. When the cellular phone roams into the visited network 14, either the visited network 14 or the cellular phone initiates attachment. If the attachment is successful, then, when the cellular phone requires use of network resources, such as access to another cellular phone in the first PDN 15-1, the cellular phone connects to the first PDN 15-1.
The visited network 14 includes one or more attachment points (collectively referred to as attachment points 20). For example, five attachment points 20-1, 20-2, 20-3, 20-4, and 20-5 are shown. The attachment points 20 may include any suitable wireless or wired interface. For example, the attachment point 20-1 may include a 3GPP interface. The attachment point 20-1 may use the Universal Mobile Telecommunications System (UMTS), a Long Term Evolution (LTE) Radio Access Network (RAN) and/or an Evolved Universal Terrestrial Radio Access Network (EUTRAN).
For example, the attachment point 20-2 may include a Worldwide interoperability for Microwave Access (WiMAX) interface. The attachment point 20-3 may include a wired interface, such as a cable modem or a Digital Subscriber Line (DSL). The attachment point 20-4 may include a 3GPP-2 interface, which may use Code Division Multiple Access 2000 (CDMA2000). The attachment point 20-5 may include a Wireless Local Area Network (WLAN) interface.
The attachment points 20 may communicate with other networks, such as the home network 13, via a serving gateway 22, which therefore acts as an anchoring point. The serving gateway 22 may also include switching and routing functionality to allow the attachment points 20 to communicate between each other. The visited network 14 may include an AAA proxy server 24, which communicates with the AAA server 18 of the home network 13.
The serving gateway 22 may communicate with a second PDN gateway 26 of the visited network 14. The second PDN gateway 26 may communicate with a second PDN 15-2. The serving gateway 22 may provide a different IP address for each PDN 15-1, 15-2 from the respective gateways 16, 26. The UE 12 may not be aware of the multiple IP addresses and may always initiate network communications with and connect to the first PDN 15-1 of the home network 13 via the visited network 14. The home network 13 may then allow “local breakout” to occur. Local breakout involves the UE 12 communicating with a device in the second PDN 15-2, which may be local to the visited network 14. Prior to local breakout, the UE 12 and the first PDN 15-1 sever connectivity.
For example, the UE 12 is shown attached to the attachment point 20-1. When the UE 12 initiates the attachment to the attachment point 20-1, the attachment point 20-1 determines whether the UE 12 is authorized by querying the AAA proxy server 24. The AAA proxy server 24 may identify the AAA server 18 based on identification information from the UE 12 and may also request authorization information from the AAA server 18.
The AAA proxy server 24 may cache data from the UE 12 for a specified period of time or for as long as the UE 12 is attached to one of the attachment points 20 of the visited network 14. In addition, the AAA server 18 may provide an expiration time for this authorization information. The authorization information may include whether the UE 12 is authorized to connect to the visited network 14, what resources the UE 12 should be offered, and what quality of service the UE 12 should be guaranteed.
In various implementations, the AAA proxy server 24 may provide the address of the AAA server 18 to the attachment point 20-1, which then queries the AAA server 18 directly. Access and authorization may be provided by any suitable method, including a home subscriber server (HSS).
Connections between the UE 12 and gateways 16, 22, 26 may be referred to as tunnels. The UE 12 may exchange information and access resources through the tunnels. When tunnels are set-up between the PDN gateways 16, 26 and the UE12, the UE is considered connected to the respective PDNs 15-1, 15-2. Assuming that the UE 12 is authorized to attach, a first tunnel is created between the attachment point 20-1 and the serving gateway 22. A second tunnel is created between the serving gateway 22 and the first PDN gateway 16. If the UE 12 requests communication with a device in the second PDN 15-2, and the home network 13 grants the request, the second tunnel is closed. A third tunnel is then created between the serving gateway 22 and the second PDN gateway 26. However, if the UE 12 switches from the attachment point 20-1 to another of the attachment points 20, or to another 3GPP attachment point (not shown), only the first tunnel may be modified.
Referring now to FIG. 3, an example of a timeline of steps performed when the UE 12 connects to the home network 13 via the visited network 14 is presented. The UE 12 may be a first cell phone that connects with the first PDN 15-1, which may be the Internet. The UE 12 performs access and authentication with the attachment point, such as the attachment point 20-1. This may include communicating with the AAA server 18. Upon authentication, the UE 12 attempts to attach to the attachment point 20-1. The AAA server may use an identifier of the UE 12, such as a network address identifier, that uniquely identifies the UE 12.
The UE 12 may request an IP address from the attachment point 20-1. The attachment point 20-1 may determine that there is a home network 13 and may request the serving gateway 22 to enable communications with the home network 13. The attachment point 20-1 may also provide an indication that the attachment point 20-1 is bound to the UE 12. The serving gateway 22 in turn communicates with the home network 13 and requests an IP address, IP1, from the PDN gateway 16.
The serving gateway 22 sends binding acknowledgement messages to the attachment point 20-1 from the PDN gateway 16. The binding acknowledgement messages include IP1. A tunnel is then set up between the serving gateway 22 and the PDN gateway 16 for transmission of packets to and from the UE 12. The attachment point 20-1 then assigns IP1 to UE 12. The UE 12 may not be aware that it is connected to the visited network 14.
If the home network 13 is aware that the second PDN 15-2 includes a device that the UE 12 is attempting to communicate with, the home network 13 may allow local breakout to the second PDN 15-2. However, this allowance is after connection to the home network 13 and first PDN 15-1 has been established, as previously discussed regarding the timeline of FIG. 3. Communications with and connection to the first PDN 15-1 are then halted, and the serving gateway 22 requests an IP address, IP2, from the second PDN gateway 26. The serving gateway 22 sends binding acknowledgement messages to the attachment point 20-1 from the second PDN gateway 26. The binding acknowledgement messages include IP2. A tunnel is then set up between the serving gateway 22 and the second PDN gateway 26 for transmission of packets to and from the UE 12.